The present invention relates to a method and system for photographic processing. The invention is particularly suitable for use in single chamber processing systems such as, for example, the system disclosed in U.S. patent application Ser. No. 09/920,495 in the name of Twist et al.
In conventional methods for processing photographic material, such as film, a number of distinct stages are involved such as, for example, developing, fixing/bleaching and washing stages. In a multi-chamber processing system, the film passes sequentially through each of these stages to produce the negatives, which are used to prepare developed photographs or scanned images. In a single-chamber system, all of the stages take place sequentially in a common chamber.
After the washing stage the film is usually dried before, as a final step of the processing, it is scanned or used together with photographic paper to produce an end product. The rate at which film can be processed is determined by the rate at which access to the chemical processing chamber (or chambers) of the processing system can be achieved. In a batch type process the time taken to remove film from the chemical processing chamber determines the overall utilisation of the system. Where the xe2x80x9crate determining stepxe2x80x9d for the process is external to the processing chamber, such as a low end type scanner, or slow dryer, it is only once the film has passed these stages that the processing chamber may become available to accept subsequent films.
For example, if scanning takes 20 seconds per frame (exposure) of the film then for a 40-exposure film the scanning stage alone takes 800 seconds. It is only once a film has substantially passed through the scanning stage that the next film to be processed can be provided to the processing chamber (or chambers) of the processing system. This problem is particularly noticeable in batch processing in a single chamber processor.
According to a first aspect of the present invention, a photographic processing system, includes: a first processing stage to process photographic material; and a second processing stage to further process the photographic material. A storage device provided between the first processing stage and the second processing stage receives and stores photographic material output from the first processing stage prior to output to the second processing stage. Thereby, the photographic material can be output from the first processing stage at a different rate than that at which it is input to the second processing stage.
Preferably, the first processing stage comprises one or more of developing, fixing, bleaching, combined fixing/bleaching and washing. The photographic material may be film, in which case the second processing stage may comprise scanning the developed film.
Preferably, the storage facility comprises a wet slack box having one or more path defining means such as rollers to define a storage path for photographic material that is output from the processing stage prior to entry into the scanning stage. Any other suitable sort of device may be used to define a path for the photographic material in the storage device such as, for example, an air knife. Preferably, the path defining means are moveable with respect to the webbing (and each other when there is more than one) to vary the length of the storage path.
In one preferred example of the present invention, the storage device also performs a drying function. In an alternative example, the storage device may be used as a final wash stage.
According to a second aspect of the present invention, a method of processing photographic material includes the steps of: processing the photographic material in a first processing stage; and storing the processed photographic material output from the first processing stage in a storage device. The storage device receives and stores a variable amount of the processed photographic material. The stored photographic material is provided to a second processing stage after a predetermined time interval.
According to a third aspect of the present invention, a photographic processing system includes: a processing stage to process photographic material and a drying stage to dry the photographic material after it has been processed by said processing stage. A storage device between the processing stage and the drying stage receives and stores the photographic material output from the processing stage to enable the material to be output from the processing stage at a different rate than that at which it is input to the drying stage, wherein heat from the processing system is provided to the storage device to at least partly dry the photographic material therein. A detector detects a parameter of the photographic material in the storage device and controls the drying stage in dependence thereon. Preferably, the heat provided from the processing system is exhaust heat from the drying stage.
The present invention provides a system in which the photographic material is able to exit the processing stage of the system at a different rate from that at which it enters the scanning stages. This effectively separates the scanning stage from the processing stage and enables the processing chamber(s) to be emptied before the scanning of the previous film. If the processing chamber is emptied, processing of the next film in sequence can start earlier than would otherwise have been possible thereby reducing the overall cycle time taken to process the films. This is particularly relevant to a single chamber batch processing system.
The use of rollers in a wet slack box provide a mechanically simple and robust system which enable photographic material to be stored safely prior to entering the scanner of the photographic system. In addition, where the rollers are moveable relative to each other the path length of photographic material stored in the slack box is variable enabling the amount of material stored to be controlled as desired in any particular situation.
By providing drying function to the storage device, the drying time of the material in the scanner can be greatly reduced. This means that the path length can be reduced of the material, which enables the overall system footprint to be correspondingly reduced.
When the storage device is used as a final wash stage it is possible to achieve faster access to the processing chamber.
In the third aspect of the present invention, a detector is provided to detect a parameter of the film stored in the storage device and provide a corresponding signal to the dryer. This parameter may be, for example, the humidity of the air in the storage device, which is related to the level of moisture contained in the stored film. Once this is known, the temperature in the dryer or the speed of passage of film through the dryer can be changed accordingly to improve the dryer efficiency.